Waiting to remit funds until the year after they were obtained

Hello. Will precede question with background. If a similar question has already been asked, please advise. Insight from experts like u/starkimpossibility and u/shrubbery_herring also appreciated.

  1. U.S. citizen, current NPR in Japan (27 Jun 2026 marks 5 years).
  2. I hold Vanguard ETFs whose total value exceeds the equivalent of 50,000,000 yen.
  3. Married Japanese national in 2025.
  4. Did not sell any Vanguard holdings in 2025.
  5. Will build house on wife's grandmother's lot this year.

To my understanding, beginning in 2027, must annually declare overseas assets on RFA.

To my understanding, as an NPR who neither generated foreign-sourced income through the sale of ETFs nor made any remittances in 2025, my 2025 dividend income (automatically reinvested) is also not subject to tax.

My question stems from point 5:

Began our housemaker search in late 2025.
Gave up on Sweden House (cost-prohibitive), landed on ecoa House.
House budget is 45,000,000.
Suruga Bank is forecasted to loan around 30,000,000.
Will sell a portion of ETFs (foreign-sourced income) to pay remaining house payment.

Question: If I sell this year (2026, NPR) but do not remit until next year (2027, permanent tax resident), is the foreign-sourced income taxable?

by PencilMeInPenguin